In general, closure fastening devices for use in connection with plastic bags, sheets, and the like are known. Furthermore, manufacturing methods for closure fastening devices made of plastic material are generally well known. Preferably, a closure fastening device should be suitable for economical manufacturing and should be relatively simple in design. In addition, the design should provide for variations in order to meet different needs. For example, it may be desirable to have a closure fastening device which enables occlusion of the closure elements at a variety of locations such as at random interdigitating positions. It is also desirable that, in operation, the closure fastening device be relatively easy to open or deocclude from the exterior of an occluded area, but be relatively difficult to deocclude from the interior of an occluded area so as to maintain the security of any contents therein.
When a closure fastening device is employed with a container, the container may be made from a thermoplastic material and the closure device and sidewalls of the container can be made integrally by extrusion as a unitary piece or can be made as separate components which are subsequently permanently connected together. The attachment of interlocking closure fastening devices to plastic sheeting is a well-known and established art involving either coextrusion of the closure elements and the film, or extrusion of either the closure elements or the film on the other after separate extrusion. Where both the closure elements and the film are extruded separately and stored for subsequent connection, they can then be joined by heat-seal or adhesive methods generally known to the artisan. Apparatus for such joining methods is also generally available.
A closure fastening device adapted to connect different parts of a plastic film to itself, or separate plastic films to each other, would permit the construction of a variety of new products, such as for example, a low cost VELCRO.RTM. type fastening device. That is, one of the closure elements may be constructed as to be present in more than one location spaced apart in parallel to permit size variations of assorted final products. For example, an interlocking closure fastening device enabling multiposition occlusion of the fastening device may be employed to provide useful products such as variable-depth pouches, storage or hanger garment bags, to clip together sheeting, and to make large covers from a number of smaller sheets.